Sheet feeding mechanism



y 1965 J. G. L!EBENOW ETAL SHEET FEEDING MECHANISM Original Filed July 11, 1960 4 Sheets-Sheet l mmvrons, J. 6. Azlsqnow BY @Zerifdzebgkz ou Samuel 11/ JUN J. G. LIEBENOW ETAL May 4, 1965 SHEET FEEDING MECHANISM Original Filed July 11, 1960 4 Sheets-Sheet 2 INVTORS: :1 6' ll'efienaw BY alas; I Az'efien 014 50211116! Milk/u? Aft if y 1965 J. G. LIEBENOW ETAL 3,181,860

SHEET FEEDING MECHANISM 4 Sheets-Sheet 3 Original Filed July 11, 1960 INVENTORS; d 6 Az'ebepau/ By 2260-27: Lzeenow y 4, 1965 J. G. LIEBENOW ETAL 3,181,860

SHEET FEEDING MECHANISM Original Filed July 11, 1960 4 s t -s t 4 1 2% w x I n I is Mill!!! 0 Ill m INVENTOR$.- 6- Amie/vow United States Patent "Ice 3,181,860 SHEET FEEDING MECHANISM Julius Gustave Liebenow, 1536 Cuyler, Bel-Wyn, Ill., and

Gilbert I. Liebenow, 400 N. Main St., Mount Prospect, Ill. Continuation of application Ser. No. 41,932, July 11, 1960. This application Jan. 16, 1963, Ser. No. 252,277 Claims. (Cl. 27132) This invention relates generally to a mechanism for feeding sheets of paperboard, cardboard and the like to a creasing and die-cutting machine or other treating machinery, and more specifically to an improved feed mechanism which is adapted to handle and feed both flat and warped blanks.

This application is a continuation of our copending application of the same title, filed July 11, 1960, US. Serial No. 41,932 now abandoned.

In machines of the character referred to, stiff blanks or like sheets are arranged in a feed pile from which they are fed one by one from such pile of sheets into the nip of the feed rolls or other feed mechanism which is operable for carrying the sheets successively into position to be acted upon, such as by creasing and/or die-cutting means. Such sheets or blanks have a normal tendency to warp or to be otherwise deformed to such extent that the next sheet in the pile to be fed frequently cannot be reliably effectively engaged by the feed mechanism to Withdraw the same from the pile and to deliver it to the treating mechanism.

In the past, attempts have been made to employ a vacuum cup or sucker as a means by which the next blank to be fed is grasped. In such usage, cups having soft lips or rims to engage the blank have been employed which thereby yield very slightly to overcome the effects of uneven or slightly inclined surfaces, such as may be found in sheet metal. However, we have noted that such structure is unreliable or even inoperative when employed for feeding paperboard blanks which are badly warped.

It has also been known previously to use supplemental grasping means for the blank to be fed, such as a plurality of sharp points which slightly penetrate the paperboard blank, and which are driven in a blank-feeding direction to insure movement thereof. It is apparent that the use of such a device, known in the trade as a corn is disadvantageous in that the workpiece or blank becomes thereby slightly marked or partially perforated. A further disadvantage to such structure is that added mechanism is provided.

It has also been known previously to employ a mechanical pusher or pushing means which engages the trailing edge of the blank to aid in the feeding movement thereof. Structures of this type are disadvantageous in that where a large blank is to be fed, a rather large reciprocatory feed mechanism is necessitated.

Although the principles of the present invention may be included in variou feed mechanisms, a particularly useful application is made in a feed mechanism of a type which is adapted to handle relatively large and stiff paperboard blanks, in which blanks, owing to their size, the warpage problem becomes accented. The present invention contemplates the utilization of, inrthe preferred embodiment disclosed herein, a number of coacting features by which badly warped paperboard blanks may be reliably fed, even though only vacuum cup means are employed to have a driving connection with the blank to be fed. Thus, by omission of any comb, marking of the blank is avoided, and by omission of any pusher mechanism, the size of the feed mechanism is such that it may be smaller than the blank being fed.

When paperboard is warped, the surface to be engaged 3,181 ,860 Patented May 4, 1965 by the vacuum cup means may be either convex or concave, and may be curved about either a line parallel to the direction of feeding or about a line extending transversely thereto. Moreover, the warpage may comprise a combination of two, three, or four of these types of warpage, the extent of which and direction of which may be dissimilar between successive blanks. The embodiment of the machine disclosed herein has been success fully employed with all these types of warpage in the blanks, the amount of warpage present being of various angles with respect to a true plane, and being displaced from such plane as much as two and one-half inches. In such embodiment, there is employed a group of suction cups supported on a transverse bar, which bar is moved through feed and return strokes. The bar itself is rockable about its longitudinal axis, is biased to a normal attitude wherein it extends substantially perpendicularly to the blank face to be engaged, and is guided so that its movement toward the face to be engaged is linear. In addition to such yieldability as may be built into each of the cups or the lips thereof, each cup is supported in spaced relation from the bar by a flexible conduit which is resiliently yieldable so that the cup can tilt in any direction away from vertical to seat squarely against the engaged face of the blank. Preferably, each blank is engaged by at least two of such cups, each of such two cups being connected to an independent source of negative pressure. By such structure, if a greater warpage is present than a particular cup can accommodate, any air leakage past such cup will not affect the negative pressure present at the other cups associated with the other source of negative pressure but acting on the same blank, such other cups being then effective to feed the blank. Thus, structure is provided to adjust the attitude of the suction cups to insure proper seating thereof against not only fiat sheets or blanks, but also against badly warped or dis- 1 torted blanks.

It is therefore an object of the present invention to provide an improved sheet feeding mechanism.

Another object of the present invention is to provide a sheet feeding mechanism which is adapted to feed warped blanks.

A still further object of the present invention is to provide a novel sheet feeding mechanism of the charac ter described which is inexpensive to manufacture and to maintain, and which is positive and accurate in its operation.

A still further object of the present invention is to pro vide a reliable sheet feeding mechanism of the type described wherein suction cup means are the sole driving means that engage the sheet to be fed.

Yet another object of the present invention is to provide means by which an individual suction cup may be oriented by the sheet to be fed, into proper seating engagement with such sheet.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a longitudinal vertical sectional view through the sheet feeding mechanism, shown in association with the sheet receiving end of treating machinery.

' FIGURE 2 is a transverse vertical sectional view taken substantially along line 2-2 of FIGURE 1.

FIGURE 3 is an enlarged detail sectional view of the feed mechanism taken along line 3-3 of FIGURE. 2.

FIGURE 5 is a fragmentary vertical sectional view of the feed mechanism taken along 55 of FIGURE 3, but showing the right-hand side as viewed in FIGURE 2, and illustrating the eccentrics in elevation.

FIGURE 6 is a fragmentary plan view of the feed mechanism taken substantially along line 66 of FIG- URE 5.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a sheet feeding mechanism such as illustrated in the drawings. The feed mechanism has been illustrated in the accompanying drawings in association with a sheet treating machine, generally illustrated at 11. The machine 11 may be a creasing and die-cutting machine and it includes a pair of spaced apart upstanding side walls 12 and a pair of cross ties 13, 14 connecting the side walls 12 so as to afford a rigid frame structure upon which is arranged one or more feed belts 15 trained over a pair of rollers 16. The machine 11 further includes a plurality of feed rolls 17 arranged at the receiving end of the belts 15, and a suitable number of hold down rollers 18 adapted to rest upon the top surface of a sheet being advanced toward the treating mechanism (not shown) on the belts 15. A motor 19 provides drive means for the treating mechanism belts 15 and the rolls 17. Since this drive does not constitute a novel part of the present invention, it has not been illustrated.

The mechanism for supporting a pile of sheets and the means for feeding said sheets one at a time from the bottom of the pile into the nip of the feed rolls 15 is mounted in an auxiliary frame structure including a pair of spaced side panels 21 which are contiguous to and which are mounted on the frame side walls 12. The side panels 21 extend rearwardly beyond the feed end of the treating mechanism frame. The side panels 21 are interconnected rigidly by one or more transverse braces 22.

A pile of sheets 23 to be fed to the feed rolls is supported on the upper end of the auxiliary frame structure and adjacent to its rearmost end on a pair of transverse supports 24. The sheets 23 are maintained in substantial alignment by a pair of adjustable side guides 25 and a pair of rear guides 26. The leading edges of the sheets 23 abut against a caliper plate 27 which is adjustable vertically to vary the gap therebeneath, and through which a sheet is passed during a feeding operation. As shown in FIGURE 1, the caliper plate 27 is guided on its ends in a pair of vertical guides 28 mounted on the side panels 21. The caliper plate 27 carries on its forwardly disposed face a number of bearings 29 providing mounting means for a number of arms 31 which carry the hold down rollers 18.

Mounted on the inside face of each side panel 21 and adjacent to the upper edges thereof is a rail 32 that extends forwardly from beneath the pile of sheets to a region closely adjacent to the feed rolls 17. The rails 32 constitute tracks along which the sheet feeding mechanism, described below, is adapted to reciprocate. As best shown in FIGURES 36 inclusive, a carriage is mounted on and extends between the guide rails 32. The carriage includes a transverse inverted channel-shaped beam 33 having a pair of elongated shoes '34 respectively integral with each of the ends of the beam 33, and respectively slidably engaged with the rails 32. Each of the shoes 34 includes a vertically disposed end portion 35 formed with a vertical channel or guide means 36 on its inwardly disposed face. A pair of slide blocks 37 arerespectively mounted on each of the portions 35 and are guided in the channels 36 thereof for vertical movement during operation of the sheet feeding mechanism. The blocks 37 constitute bearing journals for the round ends 38 of a suction cup mounting bar 39 extending transversely of the frame.

As best seen in FIGURES 5 and 6, the major portion of the bar 39 is substantially square in cross-section, and each of the round ends 38 thereof carries a collar 41 and a coil spring 42 of the torsion type. One end of each spring 42 is anchored in its respective collar 41 and its other end is anchored in the respective slide block 37. The springs 42 retain the bar 39 normally in a specific rotational or centered relationship with respect to the slide blocks 37 The bar 39 may thus be rocked about its longitudinal axis in either direction from the normal position against the force of the springs 42. Rotational movement or rocking of the bar 39 in one direction may be assisted by a weight 40.

Insofar as the structure has been described, the bar 39 is mounted for rotational or rocking movement in the slide blocks 37 and the blocks 37 are vertically slidable and guided in the carriage shoes 34 which in turn are longitudinally slidable along the guide rails 32. The feed mechanism includes means described below to automatically move the bar 39 through a continual cycle of horizontal and vertical reciprocation during feed operation, one such cycle comprising a feed stroke and a return stroke.

The bar 39 of this embodiment carries a plurality of suction cups 43 each of which cups is mounted on and spaced above one of a number of blocks 44 for longitudinal adjustment along the bar 39, a setscrew 45 being provided in each block 44 to secure it in a selected adjusted position. In use, the suction cups 43 are arranged so as to engage the surface of the adjacent sheet, which in this embodiment comprises the lowermost sheet in the pile of sheets, irrespective of the amount or direction of warp therein, and to withdraw the engaged sheet through the gap and feed it into the nip of the feed rolls 17. In the instant embodiment, there are four mutually spaced apart suction cups 43, each of which has an individual inherent degree of resiliency or flexibility, and each of which is mounted on the bar 39. Alternate ones of the cups 43 are connected, such as in pairs, by means of a pair of flexible conduits 46, 47 to a pair of valve elements 48, 49 respectively, and a pair of conduits 51, 52 connect the valve elements 48, 49 one to each of a pair of pumps 53, each pump 53 being operatively connected by a common belt 54 to an electric drive motor 55. The valve elements 48, 49 normally are closed and means described below is operable automatically during machine operation in synchronization with reciprocation of the carriage 30 to open and then to close both of the valves 48, 49, in unison, to alternately apply and relieve a negative pressure or suction force to the suction cups 43. The use of two pumps 53 and two control valves 48, 49 for selectively communicating the suction pumps with the source of negative pressure is preferred so that in the event that one or both of the suction cups 43 associated with one of the pumps 53 or sources of negative pressure is made ineifec tive for any reason, the operation of the suction cups associated with the other source of negative pressure is not affected thereby.

Vertical and horizontal reciprocation of the bar 39 carrying the suction cups 43 and the opening and closing of the valve elements 48, 49 is automatically effected during operation of the feed mechanism by rotation of a continually driven shaft 56 extending between and journalled at its ends in the side panels 21. As best shown in FIGURES 24 inclusive, the drive shaft 56 carries two pairs of eccentrics 57, 58, one pair being disposed inwardly from each end. Because each pair of eccentrics'and the elements engaged therewith and operable thereby are alike, the following description "covers but one such assembly, it being understood that the description is equally applicable to the other.

The eccentric 57 is engaged at all times by a roller pin 59 carried on a lever 61, the lower end of which is pivotally mounted on a fixed rod 62 bridging the side panels 21. The upper end of the lever 61 carries a link 63 pivotally connected at one of its ends to the lever 61, as at 64, and at its other end to the beam 33 of the reciprocable carriage 30, as at 65. During operation of the feed mechanism, the lever 61 is oscillatably rotated about the pivot rod 62 so as to move the beam 33 and the suction cup bar 39 mounted thereon forwardly and rearwardly along the guide rails 32, into and out of the extreme positions shown in FIGURES 3 and 4.

The other eccentric 58 of each pair of eccentrics has a roller pin 66 engaged therewith. The pin 66 is rigidly mounted in a lug '67 depending from a rocker arm 68 that is mounted. at one end on a transverse rod 69 extending between the side panels 211. The rocker arm 68 has a channel 71 on its side face extending inward-1y from its free end and in which is slida'bly engaged a stud roller 72 carried by an ear 73 depending from the suction cup bar 39. This specific drive assembly is effective to alternately raise and lower the suction cup bar 39 duringhorizontal reciprocation of the bar.

The shaft 56 also mounts a pair of eccentrics 74 arranged to operatively [cooperate with the valve elements 48, 49 for selectively opening and closing such valve elements 48, 49 during operation of the feed mechanism. The shaft 56 derives its power through a train of gears 75, 76, a gear box 77 and a drive shaft 78 connecting the gear box with the motor 19.

More specifically, the operation of the suction cup assernbly is substantially as follows? As viewed in FIGURE 3, the suction cups have been carried rearwardly and are elevated so as to be in contact with the bottom surface of the lowermost sheet in the pile of sheets. 'Any irregularity in the planula-r surface of the engaged sheet is compensated for by rocking of the linearly movable suction cup bar 39, and also by deflection of the flexible conduit which supports each of the suction cups 43 on the mounting block 44. The reslient flexibility of the cup-mounting conduits enables the cups 43 to tilt individually in whatever direction may be required to insure a seating of the sealing face thereof against the adjacent sheet. At this time, the valve elements 48, 49 are opened by operation of the eccentrics 74 so as to create a sufiicient negative pressure or suction to cause adherence of the cup to the engaged sheet.

Clockwise rotation of the shaft 56 carries the high land 58a on the eccentrics 58 out of registration with the roller pins 66 to thereby pull the suction cup bar 39 downwardly a distance suflicient to locate the leading edge of the engaged lowermost sheet in alignment with the gap below the caliper plate 27. The eccentrics 57 are rotating in a clockwise direction also, so as to rock the levers 61 in a clockwise direct-ion and to advance the carriage 30 into the forward position shown in FIGURE 4. Such movement of the beam 33 carries the suction cup bar 39 and the adhered sheet forwardly through the gap and locates its leading edge in the nip of the rolls 17. At this time, the valve elements 48, 49 are closed to interrupt suction to the suction cups 43 whereupon the sheet is freed to be drawn between the rolls 17 and to be deposited on the feed belts '15. Coincidental with the relief of suction, the cups 43 are dropped slightly by reason of the rocker arm pins 66 riding onto a smaller diameter eccentric area on the eccentric 58, and the beam 33 is carried rearwardly into its initial position whereupon it is again elevated into the position shown in FIGURE 3 to repeat the cycle of operation.

A feature of operation during feeding of the sheets is the ability of the suction cup bar 39 to oscillatably rotate in its mounting to insure that the suction cups 43, connected thereto by means of the flexible conduits, have a flat or sealing engagement with the surface of the adjacent sheet in the pile, even where such surface of the sheet is warped, curled, or otherwise disposed or displaced from the normal sheet plane. Such rocking is afiorded by the pivotal mounting of the bar 39 in the slide blocks 37, the centering springs 42 acting to return the bar to its initial position each time that it is tilted to accommodate any warp or distortion present in the engaged sheet. The guide means 35-37 insures that the cups 43 will be in their normal attitude for any length of vertical movement thereof so as to engage the lower surf-ace of the sheet 23 while in such attitude whether the point of engagement on the sheet be in its normal position or be vertically displaced therefrom due to warpage. Further, the resilient cup-supporting conduits secured adjustalbly to the bar 39 by the blocks 44 insure that each cup 43 may tilt independently of the other cups 43 to accommodate the various points of engagement on the adjacent sheet, which points of engagement may be oriented at various angles with respect to a reference plane.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.-

We claim as our invention:

1. A mechanism for feeding both fiat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

'(b) a pair of vertically guided and movable slide blocks rotatably supporting the ends of saidbar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(0) means operative to move said slide blocks vertically and other means for moving said slide blocks horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked;

(d) at least one suction cup supported on said bar and directed to engage the surface of an adjacent blank during a feed stroke, and operative to transmit a rocking tforce to said bar in response to non-seated engagement of said cup 'with a warped blank;

e) a source of negative pressure; and

(f) conduit means operative to periodically connect said source with said suction cup;

whereby any tendency for warpage-induced leakage past said cup during a feed stroke will be eliminated by the rocking movement of said bar to enable substantially leak-free seating of said cup against the warped blank.

2. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed (b) a pair of vertically guided and movable slide blocks rotatably supporting the ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(c) means operative to move said slide blocks vertically and other means for moving said slide blocks horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked;

(d) a plurality of suction cups supported on said bar in spaced relation to each other, and directed so that all of said plurality of cups may engage the surface of a single adjacent blank during a feed stroke, and operative to transmit a rocking force to said bar in response to non-seated engagement of any one of said cups with a warped blank;

(e) a plurality of continually driven sources of negative pressure;

(f) conduit means operative to periodically connect one of said sources with at least one of said cups; and

(g) other conduit means operative to periodically connect the other of said sources with the other of said cups independently of said first named conduit means;

whereby any tendency for Warpage-induced leakage past said cups during a feed stroke will be eliminated for said one cup by rocking movement of said bar to enable substantially leak-free seating of said cup against the warped blank, while any warpage-induced leakage past one of the cups associated with the other source of negative pressure and acting on the same blank will not afiect the negative pressure at said one cup.

3. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically elongated slide blocks rotatably supporting the opposite ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

() means operative to move said slide blocks vertically and horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked, said moving means carrying said guide blocks, and a horizontally movable portion of said moving means vertically guiding said guide blocks at opposite sides of said bar so as to enable a substantial amount of straight-line vertical bar movement which is in excess of the amount of vertical blank warpage to be accommodated;

(d) at least one suction cup supported on said bar and directed to engage the surface of an adjacent blank during a feed stroke, and operative to transmit a rocking force to said bar in response to non-seated engagement of said cup with a warped blank, thereby enabling said cup to tilt into seated engagement with the adjacent surface of such warped blank;

(e) a source of negative pressure; and

(f) conduit means operative to periodically connected said source with said suction cup;

whereby said cup may be linearly displaced a considerable blank-warpage distance during a feed stroke and tilted into seated engagement with a warped blank to obtain a substantially airtight grip thereon for feeding it.

4. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically guided and movable slide blocks rotatably supporting the ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(c) means operative to move said slide blocks vertically and other means for moving said slide blocks horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked;

(d) at least one suction cup supported on said bar and directed to engage the surface of an adjacent blank during a feed stroke, and operative to transmit a rocking force to said bar in response to non-seated engagement of said cup with a warped blank;

(e) means acting between said bar and one of said slide blocks and torsionally biasing said bar to a predetermined angular position in which the axis of said cup is directed substantially perpendicularly to any fiat blank;

(7) a source of negative pressure; and

(g) conduit means operative to periodically connect said source with said suction cup;

whereby any tendency for warpage-induced leakage past said cup during a feed stroke will be eliminated by the rocking movement of said bar against its torsional bias 'to enable substantially leak-free seating of said cup against the warped blank.

5. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed (b) a pair of vertically guided and movable slide blocks rotatably supporting the ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(c) means operative to move said slide blocks vertically and other means for moving said slide blocks horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked;

(d) at least one suction cup;

(6) a resiliently yieldable tube carried by said bar,

having a length greater than its diameter and extending from said bar to said cup, and supporting said cup in spaced relation to said bar, the resiliency of said tube enabling said cup to tilt with respect to said bar, in response to non-seated engagement by said cup with a warped blank, and to transmit a rocking force to said bar, said cup being normally directed with its axis substantially perpendicular to the surface of an adjacent flat blank during a feed stroke;

(1) a source of negative pressure; and

(g) conduit means operative to periodically connect said source with said resiliently yieldable tube;

whereby any tendency for warpage-induced leakage past said cup during a feed stroke will be eliminated by joint rocking of said bar about its axis and tilting of said cup with respect to said bar to enable substantially leak-free seating of said cup against the warped blank.

6. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically elongated slide blocks rotatably supporting the opposite ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(c) means operative to move said slide blocks vertically and horizontally in both a feed stroke :and in a return stroke in which strokes said bar is normally not rocked, said moving means carrying said guide blocks, and a horizontally movable portion of said moving means vertically guiding said guide blocks at opposite sides of said bar so as to enable a substantial amount of straight-line vertical bar movement which is in excess of the amount of vertical blank warpage to be accommodated;

(d) at least one suction cup;

(2) a resiliently yieldable tube carried by said bar,

having a length greater than its diameter and extending from said bar to said cup, and supporting said cup in spaced relation to said bar, the resiliency of said tube enabling said cup to tilt with respect to said bar in response to non-seated engagement by said cup with a warped blank, and to transmit a rocking force to said bar, said cup being normally directed with its axis substantially perpendicular to the surface of an adjacent flat blank during a feed stroke;

(f) a source of negative pressure; and

(g) conduit means selectively connecting said source with said resiliently yieldable tube;

whereby said cup may be linearly displaced a considerable blank-warpage distance during a feed stroke, and thereafter oriented into a substantially leak-free seated engagement against the warped blank by joint rocking of said bar about its axis and by tilting of said cup with respect to said bar.

7. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically elongated slide blocks rotatably supporting the opposite ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

() means operative to move said slide blocks vertically and horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked, said moving means carrying said guide blocks, and a horizontally movable portion of said moving means vertically guiding said guide blocks at opposite sides of said bar 50 as to enable a substantial amount of straight-line vertical bar movement which is in excess of the amount of vertical blank warpage to be accommodated;

(d) a plurality of suction cups supported on said bar in spaced relation to each other, and directed so that all of said pluraltity of cups may engage the surface of a single adjacent blank during a teed stroke, and each operative to transmit a rocking force to said bar in response to non-seated engagement of any of said cups with a warped blank;

(e) a plurality of continually driven sources of negative pressure;

(f) conduit means operative to periodically connect one of said sources with at least one of said cups; and

g) other conduit means operative to periodically connect the other of said sources with the other of said cups independently of said first named conduit means; whereby said bar and said cups may be linearly displaced a considerable blank-Warpage distance during a feed stroke to eifect engagement of at least one cup with the warped blank, which engagement will effect any necessary rocking movement of said bar about its axis to seat such cup in substantially leak-free relation against the blank, and whereby any warpage-induced leakage past another of said cups associated with the other source of negative pressure will not affect the negative pressure at said one seated cup.

8. A mechanism for feeding both fiat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically guided and movable slide blocks rotatably supporting the ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(0) means operative to move said slide blocks vertically and other means for moving said slide blocks horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked;

(d) a plurality of suction cups for acting on a single blank;

(e) a plurality of resiliently yieldable tubes individually carried by said bar, each having a length greater than its diameter and extending from said bar to one of said cups, and each respectively supporting said one of said cups in spaced relation to said bar, the resiliency of said tubes enabling each cup to tilt independently of each other with respect to said bar during a feed stroke in response to nonseated engagement by each cup with a warped blank, and to ransmit a rocking force to said bar, thereby enabling seated engagement of said cups with the adjacent surface of such Warped blank;

(f) a plurality of continually driven sources of negative pressure;

(g) conduit means operative to periodically connect one of said sources with at least one of said resiliently yieldable tubes; and

(h) other conduit means operative to periodically connect the other of said sources with the other of said resiliently yieldable tubes independently of said first named conduit means;

whereby any tendency for warpage-induced leakage past said cups during a feed stroke will normally be eliminated by joint rocking of said bar about its axis and by tilting of said cups in appropriate directions with respect to said bar to enable substantially leak-free seating of said cups against the warped blank, while any warpage-induced air leakage not eliminated past one of said cups will not afiect the negative pressure at the other of said cups acting on the same blank and associated with the other source of negative pressure.

9. A mechanism for feeding both flat and warped paperboard blanks from a pile of blanks, comprising in combination:

(a) an elongated bar arranged transversely of said feed pile;

(b) a pair of vertically elongated slide blocks rotatably supporting the opposite ends of said bar for rocking movement with respect to said blocks about the longitudinal axis of said bar;

(0) means operative to move said slide blocks vertically and horizontally in both a feed stroke and in a return stroke in which strokes said bar is normally not rocked, said moving means carrying said guide blocks, and a horizontally movable portion of said moving means vertically guiding said guide blocks at opposite sides of said bar so as to enable a substantial amount of straight-line vertical bar movement which is in excess of the amount of vertical blank wanpage to be accommodated;

(d) a plurality of suction cups;

(e) a plurality of resiliently yieldable tubes individually carried by said bar, each having a length greater than its diameter and extending frorn said bar to one of said cups, and each respectively supporting said one of said cups in spaced relation to said bar, the resiliency of said tubes enabling each cup to tilt independently of each other with respect to said bar during a feed stroke in response to nonseated engagement with a warped blank into seated engagement with the adjacent surface of such warped blank;

(1) a plurality of continually driven sources of negative pressure;

(3) conduit means operative to periodically connect one of said sources with at least one of said resiliently yieldable tubes; and

(h) other conduit means operative to periodically connect the other of said sources with the other of said resiliently yieldable tubes independently of said first named conduit means;

whereby said cups and said bar may be linearly displaced a considerable blank-warpage distance during a feed stroke to effect engagement of one cup with the warped blank, which engagement will eifect joint rocking of said bar about its axis and tilting of said one cup with respect to said bar to seat said one cup against the warped blank, while any warp-age-induced air leakage past another of said cups associated with the other source of negative pressure and acting on the same blank will not iafiect the negative pressure at said one cup.

10. A mechanism as claimed in claim 9, having means acting between said bar and one of said slide blocks and torsionally biasing said bar to a predetermined angular position in which the axis of said cup is directed substantially penpendicularly to any flat blank.

References Cited by the Examiner UNITED STATES PATENTS 768,462 8/04 Juengst 271-29 1,155,503 10/15 Moore 271-32 1,904,769 4/ 33 Skillman. 2,828,126 3/58 Labombarde 27132 ROBERT B. REEVES, Acting'Primary Examiner.

ERNEST A. FALLER, In, SAMUEL F. COLEMAN,

Examiners. 

1. A MECHANISM FOR FEEDING BOTH FLAT AND WARPED PAPERBOARD BLANKS FROM A PILE OF BLANKS, COMPRISING IN COMBINATION: (A) AN ELONGATED BAR ARRANGED TRANSVERSELY OF SAID FEED PILE; (B) A PAIR OF VERTICALLY GUIDED AND MOVABLE SLIDE BLOCKS ROTATABLY SUPPORTING THE ENDS OF SAID BAR FOR ROCKING MOVEMENT WITH RESPECT TO SAID BLOCKS ABOUT THE LONGITUDINAL AXIS OF SAID BAR; (C) MEANS OPERATIVE TO MOVE SAID SLIDE BLOCKS VERTICALLY AND OTHER MEANS FOR MOVING SAID SLIDE BLOCKS HORIZONTALLY IN BOTH A FEED STROKE AND IN A RETURN STROKE IN WHICH STROKES SAID BAR IS NORMALLY NOT ROCKED; (D) AT LEAST ONE SUCTION CUP SUPPORTED ON SAID BAR AND DIRECTED TO ENGAGE THE SURFACE OF AN ADJACENT BLANK DURING A FEED STROKE, AND OPERATIVE TO TRANSMIT A ROCKING FORCE TO SAID BAR IN RESPONSE TO NON-SEATED ENGAGEMENT OF SAID CUP WITH A WARPED BLANK; (F) A SOURCE OF NEGATIVE PRESSURE; AND (F) CONDUIT MEANS OPERATIVE TO PERIODICALLY CONNECT SAID SOURCE WITH SAID SUCTION CUP; WHEREBY ANY TENDENCY FOR WARPAGE-INDUCED LEAKAGE PAST SAID CUP DURING A FEED STROKE WILL BE ELIMINATED BY THE ROCKING MOVEMENT OF SAID BAR TO ENABLE SUBSTANTIALLY LEAK-FREE SEATING OF SAID CUP AGAINST THE WARPED BLANK. 